There are a number of conventional methods and devices in commercial practice for transmitting signals over power lines, particularly within households or commercial buildings, for use in controlling lights, appliances, and other devices, generally within the same building. Many of these methods involve modulating higher frequency signals (e.g., radio frequency (RF) signals) onto power lines that then travel the power lines where the higher frequency signals are received by a receiver and control device. Such techniques involve several additional circuits and devices and costs associated therewith. In some cases, the control and distance capabilities, and costs, are greater that what is required for many applications, such as controlling intensity of lighting.
With a general push toward more energy efficient lighting devices, and emergence of high brightness LEDs, VCSEL arrays, and other lighting technologies that are generally more energy efficient than incandescent lighting, there is an increasing need for low cost methods and apparatus for controlling intensity, spectral, and other characteristics of such devices to help realize benefits such illumination technologies can provide. For example, many potential users of these advanced illumination technologies have grown accustomed to spectral characteristics (e.g., color temperature) of incandescent lighting as well as an ability to control intensity of such lighting. Spectral characteristics of light from fluorescent tubes, both conventional straight fluorescent tubes such as have been used in commercial buildings for many years as well as more recently commercialized compact fluorescent light tubes, are generally controlled primarily by selection of phosphors used to coat an interior surface of such tubes. However, the spectral outputs of these lamps are fixed. Various studies have shown how changes in spectral characteristics from light sources affect human moods and performance in various home, office, retail, and other work environments, outdoor environments, and in entertainment settings, trade show, and other environments. Thus, an ability to change spectral characteristics of lighting as well as intensity is generally desirable for many lighting applications and human activities.
As a result, it is desirable to have a method and system to avoid these and other related problems.